Electronic counting circuit



March 30, 1965 A. SOMLYODY ELECTRONIC COUNTING CIRCUIT Filed Sept. 19, 1962 LIL .N

INVENTOR. ARPAD SOMLYODY M Q 21% ATTORNEY United States Patent 3,176,182 ELECTRONIC COUNTING CIRCUIT Arpad Somlyody, Raritan, N.J., assignor to Burroughs Corporation, Detroit, Mich., a corporation of Michigan Filed Sept. 19, 1962, Ser. No. 224,705 6 Claims. (Cl. 315-8.6)

This invention relates to electronic counting circuits and particularly to counting circuits using multi-pcsition magnetron beam switching tubes as the counting elements thereof.

Magnetron beam switching tubes include an electron emitting cathode and a plurality of groups of electrodes, each of which is adapted to receive an electron beam from the cathode and to provide an output signal therefrom. Each group of electrodes includes a target electrode from which an output signal is provided and which receives the electron beam, .a spade electn do which dorms and holds an electron beam on its associated target electrode, and a switching electrode which may be used to switch an electron beam from one group of electrodes to the next. The spade electrodes may also be utilized to perform switching function. The tube performs a counting operation as an electron beam moves from position to position within the tube.

Generally, the switching operation is controlled by an external source of pulses which are applied either to the switching electrodes or to the spade electrodes. Presently known switching circuits operate satisfactorily; however, they are relatively expensive and they sometimes operate improperly because their coupling to the beam switching tube is relatively loose. Such loose coupling sometimes produces erroneous switching of an electron beam.

The objects of the invention are concerned with the provision of a relatively simple and inexpensive counting circuit using mold-position magnetron beam switching tubes and having an efiicient coupling arrangement between each counting tube and means for g the tube.

Briefly, the counting circuit of the invention includes ones or more counting units, each of which comprises a mold-position magnetron beam switching tube as the counting element thereof. The spade electrodes of the counting tube are connected in two groups, alternate electrodes in a group, and each group is coupled through a separate transistor to a corresponding group of switching electrodes. The connections are such that, as an electron beam is switched from one group of electrodes to the next and an output pulse is registered, the spade electrode at the next position operates through its associated transistor to cause the electron beam to switch to the next leading position. This operation is performed at each counting position.

The invention is described in greater detail with reference t I the drawing wherein the single figure is a schematic representation of a counting circuit embodying the invention.

The circuit shown in the drawing is particularly suited for use with magnetron beam switcbhn-g tubes such the type 6700 tube and with similar devices sold by the Burroughs Corporation and known as BEAM-X switches. These devices are cylindrical in form, but they are shown schematically in linear form as tube It) in FIG. 1. The tube 10 has an envelope 12 which contains a central cathode 16 and ten groups of electrodes spaced radially equidistantly from and surrounding the cathode. For simplicity, only four groups of electrodes are shown numbered 0, l, 2, and 3. Each group of electrodes includes a spade electrode 26 which lies closest to the cathode and a target electrode 24 positioned behind the spade electrode. Each spade electrode serves to form and hold an electron beam on its corresponding target electrode which itself provides an output signal from the beam. A switching 3,176,182 Patented Mar. 30, 1965 electrode 28, known as a switching grid and used for switching an electron beam from position to position, is also includes in each group of electrodes. In BEAM-X switch, an auxiliary electrode is provided between each target and the adjacent leading spade, and the auxiliary electrode acts as a current collecting electrode.

The tube 152 also includes suitable means (not shown) for providing axial magnetic field which combines with electric fields the tube to form an electron beam and switch it firom one group of electrodes to the next.

Such means may be an external permanent magnet or internal magnets or the like. The direction in which an electron beam is urged, that is, clockwise or counterclockwise, is called the leading direction, and is always the same and is determined by the orientation of the electric and magnetic fields.

In the circuit of the drawing, the cathode 14 is connected to a source of reference potential such as ground. According to the invention, the spade electrodes 20 are connected in two groups, with the even-numbered eleo electrodes being coupled through resistors 30 to a first spade bus 34 and the oddsnurnbered electrodes being coupled through resistors 39 to- .a second spade bus 38.

The target electrodes 24 are connected through suitable load resistors 42 to a common [target bus 44 which is coupled to a positive DC. power supply V or about 300 volts. In addition an auxiliary output tap 45 is provided at each target for connection to a suitable utilization device or circuit, for example, the cathodes of an indicator tube, or a printing mechanism or the like.

A reset circuit 46 is provided for clearing an electron beam tube 16 and resetting it at the 0 position at the beginning of .a counting cycle. The reset circuit 46 includes means for applying a positive pulse to the cathode 14-, this pulse. serving to clear :a beam in tube 10. The reset circuit is also adapted to apply a negative pulse to the() spade to cause an electron beam to form at the 0 position after the tube has been cleared. The reset circuit is also adapted to apply a negative pulse to the base electrode 69 of transistor 54 to turn on transistor 54 at the beginning 'OEf a counting cycle.

According to the invention, a pair of similar PNP transistors 50 and 54 are provided for assisting in the performance of the switching or counting function. Transistor 50 includes emitter, base, and collector electrodes 65), 61, 62, respectively, and transistor 54 includes emitter, base, and collector electrodes 68, 69, 70, respectively. The base electrodes 61 and 69 are coupled through suitable bias resistors '74 and 76 to: a bus 80 which is connected to a positive DC. power source V. The emitter electrodes 60 and 68 are connected together and through a bias resistor 84- to the bus 80. The collector electrodes 62 and 70 are connected through separate resistors 88 and 9t] to a source of reference such as ground. In addition, the collector 62 of the transistor 50 is coupled to the set of even-numbered switching electrodes 23. The collector electrode 7 0 of the transistor 54 is similarly connected to the set or" odd-numbered switching electrodes 28. The base electrode 61 of the transistor 50 is coupled to bus 34 and thus to the even-numbered spade electrodes. The base electrode 69 of the transistor 54 is similiarly coupled to bus 38 and thus to the odd-numbered spade electrodes.

The collector electrode 62 of transistor 50 is coupled through a capacitor 94 to the base electrode of the transistor 54, and the collector electrode 70 of the transistor 54 is similarly coupled through a capacitor 98 to the base electrode 61 of transistor 50. Each base electrode is also coupled through a separate capacitor 100 to a source 104 of counting pulses. If tube 10 is an intermediate stage in a chain of counting steps, then the pulse source 104 may be replaced by one of the electrodes, for example,

. 3 the spade electrode at the carry position in the counting tube which precedes tube 10.

In'operation of the invention, at the beginning of a counting cycle, the reset circuit 46 is employed to set an electron beam at the position and to turn on trans sistor 50. With transistor 50 turned on, its collector electrode 62 is at a generally positive potential which is coupled through capacitor 94 to base electrode 69 of transistor 54 which is held off thereby. With an electron turned on, its collector electrode 7th rises to a positive po-- tential which is coupled to the base 61 of transistor 50, whichis thus turned oii. At the same time, the collector 62 of transistor 50 is reduced to about ground potential, and this potential is applied to the switching grid elec trode at the, 0 position whereby the electron beam at the 0 position is'switched to the 1 position. The next counting pulse from source 104 reverses the condition of the transistors 50 and 54 and causes a beam switching pulse "to'be applied to the switching grid at the 1 position. The beam is thus switched tothe 2 position. In this way, an electron beam may be switched from position to position.

From the foregoing description of the invention, it can be seen that the transistors '50 and 54, which cause 7 an electron beam in tube 10'to be switched from position to position, are intimately connected to the beam switching tube by means of their base electrodes being coupled to the. spade electrodes of the tube and their collector electrodes being coupled to the switching electrodes of the tube. More efiicient switching is thus attainable.

This ararngement also facilitates switching of an electron beam when the source of switching puls'es'is a preceding 7 beam switching tube.

What is claimed is: I V l. A counter circuit including an electron beam switching tube having a cathodeand a plurality of groups of electrodes; each group including a target electrode which 7 sets with 4 comprising input means and said collector electrodes comprising output means, said emitter electrodes being connected to a source of reference potential.

3. The circuit defined in claim l wherein said electron discharge devices comprise transistors each having emitter, collector, and base electrodes, said base electrodes comprising input means and said collector electrodes comprising output means, said emitter electrodes being connected to a source of reterencepotential,

the collector electrode of the first transistor being coupled to the base electrode of the second tansistor and the collector electrode of the second transistor being coupled to. the base electrode of the first transistor whereby each transistor, when it is turned on, can hold off the'other transistor.

4. The'circuit defined in claim 1 wherein said electron discharge devices comprise transistors each having emitter, collector, and base electrodes,

the emitter electrodes of the transistors being connected to a source of reference potential,

the collector electrode of the first transistor being coupled to the base electrode of the second transistor and the collector electrode of the second transistor being coupled to the base electrode of the first transistor whereby each transistor, when it is turned on, can hold on the other transistor,

the collector electrode of the first transistor also being connected to one setof switching electrodes while the base electrode of the first transistor is connected to the corresponding set of spade electrodes,

the collector electrode of the second transistor being connected to the other set of switching electrodes with the base electrode of the second transistor being connected to'theycorresponding set of spade electrodes, V

the interconnections being such that, when one of the f transistors is turned on, it turns off the other transistor,'the other transistor in turn then applying a switching pulse to the. switching electrodes to which it is connected whereby an electron beam is switched from one position to'th'e next. 7 V

5.. The circuit deiined in claim 1 wherein said electron discharge devices comprise transistors each having emitter, collector, and base electrodes, said base electrodes comprising input means and said collector electrodes comprising output means, 'said emitter electrodes being connected to a source'of referenc'e potential,

a first electron discharge device having input means and output means with the input means being coupled 7 to one set of spade electrodes and the'output means being coupled to the same set of switching electrodes; a second electron discharge device having input means.

and output meanswith the inputmeans being coupled to the second set of spade electrodes and the out- 7 put means being coupled to. the second set of switching electrodes; r q V said. electron discharge devices being interconnected so that when one is in afirst conductive state, it

holds the other in the opposite conductive state;

the collector electrode of the first transistor being capacitively coupled to the base electrode of the second transistor and. the collector electrode of the second transistor being capacitively coupled to the base electrode of the first transistor whereby each transistor, when it is turnedon, can hold off the-other transistor,

said source of switching pulses being coupled to the base electrodes of saidtransistors.

6. A counter circuit including an electron beam switching tube having a cathode and a plurality of groups of electrodes-arbitrarily numbered O, l, 2 it; each group including a target electrode which receives 'an electron beam and produces an output signal therefro1n,.a spade electrode which holds an electron beam onits associated target. electrode, and a switching electrode which serves to switchanelectron beam from one the emitter electrodes of said transistors being consistor being connected to the corresponding set of nected to a source of reference potential; odd-numbered spade electrodes;

the collector electrode of the first transistor being the interconnections being such that, when one of the coupled to the base electrode of the second transis transistors is turned on, it turns 01f the other trantor and the collector electrode of the second tran- 5 sistor, the other transistor in turn then applying a sistor being coupled to the base electrode of the first switching pulse to the switching electrodes to which transistor whereby each transistor, when it is turned it is connected whereby an electron beam is switched on, can hold ofl the other transistor; from one position to the next.

the collector electrode of the first transistor also being connected to the set of even-numbered switching 1O References Cited y the Examine! electrodes while the base electrode of the first tran- UNITED STATES PATENTS sistor 1s connected to the corresponding set Or even- 3,079,528 2/63 somlyody 340 168 X numbered spade electrodes;

the collector electrode of the second transistor being connected to the set of odd-numbered switching elec- 15 GEORGE WESTBY {primary Exammer' trodes with the base electrode of the second tran- APTHUR GAUSS, Examine?- 

6. A COUNTER CIRCUIT INCLUDING AN ELECTRON BEAM SWITCHING TUBE HAVING A CATHODE AND A PLURALITY OF GROUPS OF ELECTRODES ARBITRARILY NUMBERED "0," "1," "2," ..."N"; EACH GROUP INCLUDING A TARGET ELECTRODE WHICH RECEIVES AN ELECTRON BEAM AND PRODUCES AN OTUPUT SIGNAL THEREFROM, A SPADE ELECTRODE WHICH HOLDS AN ELECTRON BEAM ON ITS ASSOCIATED TARGET ELECTRODE, AND A SWITCHING ELECTRODE WHICH SERVES TO SWITCH AN ELECTRON BEAM FROM ONE GROUP OF ELECTRODES TO THE NEXT; SAID SPADE ELECTRODES BEING CONNECTED IN TWO SETS WITH ODD-NUMBERED SPADES BEING IN ONE SET AND EVENNUMBERED SPADES BEING IN THE OTHERE SET; SAID SWITCHING ELECTRODES BEING CONNECTED IN TWO SETS WITH THE ODD-NUMBERED SWITCHING ELECTRODES BEING CONNETED IN ONE SET AND THE EVEN-NUMBERED SWITCHING ELECTRODES BEING CONNECTED IN THE OTHER SET; TWO TRANSISTORS EACH HAVING EMITTER, COLLECTOR, AND BASE ELECTRODES; THE EMITTER ELECTRODES OF SAID TRANSISTORS BEING CONNECTED TO A SOURCE OF REFERENCE POTENTIAL; 